1. Field of the Invention
The present invention relates to a rack and pinion type steering gear configured to a rack bar, which comprises a rack teeth portion, a link, and a sliding portion.
2. Description of the Related Art
A steering gear box is an interconnect mechanism which transforms rotation of the steering wheel to a linear translation by means of the rack-pinion mechanism. The linear translation of the rack steers the tires of the vehicle through a tie rod assembly and a knuckle.
FIG. 1 illustrates the prior art a rack and pinion type steering gear. As shown in FIG. 1, the rack and pinion type steering gear 10 comprises a pinion 20, a rack bar 30 having a rack teeth 35 engaged with the pinion 20, a first tie rod 40a and a second tie rod 40b disposed at both right and left ends of the rack bar 30, and a first ball joint 50a and a second ball joint 50b for connecting the rack bar 130 with the first and second tie rods 40a, 40b (Refer to U.S. Pat. No. 4,721,175).
The pinion 20 is formed at the end of a pinion shaft 25 which is connected to a steering shaft (not shown).
The Rack bar 30 is a long round rod for converting rotation of the pinion 20 into a linear translation, and is slidably inserted into a tube type rack housing 70. The rack housing 70 is fixed on a frame (not shown).
The first and second ball joints 50a and 50b are covered with bellows 60a and 60b. The bellows 60a and 60b are fixedly mounted on the tie rods 40a and 40b and the rack housing 70.
However, the above-described rack bar 30 linearly moves in an axial direction in the housing 70. Therefore, if the rack bar 30 has a deviation in straightness, or the housing 70 has a deviation in roundness, it is likely to have a friction problem that reduces a basic performance of the steering gear.